"Originally stemming from MeeGo, birthed under Nokia's watch, Sailfish has since gone its own way and is maturing into a mobile platform getting ready for launch. This week at the Mobile World Congress, we tracked down Jolla and Mosconi again, getting the opportunity in the process to check out a live Sailfish demo. We check out how notifications work, look at the Sailfish take on a status bar, and get to see the media player with all its gesture support." By far the most unique and interesting of the alternative mobile platforms. Very fancy.

Porting desktop apps to mobile devices usually involves rewriting the interface for the form factor. Many linux desktop apps are not written in a way where the UI is cleanly separated from the backend. So porting desktop apps to mobile may be more involved than you suggest. Also, most mobile linux distributions do not come with the libraries that are usually bundled on the desktop distributions. Getting those libraries on the mobile OS may be simple or tedious depending on the library.

I do not understand this popular claim that it is simple to port desktop apps to a mobile interface and form factor.

I do not agree with your opinion about the Ubuntu mobile effort but I will not get into that now.